EESA11H3 Lecture Notes - Lecture 6: Ozone Depletion, Chloromethane, Sulfur Dioxide
Document Summary
The ozone-layer: is a shield in the earth"s stratosphere that absorbs most of the sun"s ultraviolet radiation. More uv radiation reaches the equator, as well as at higher elevations. Other air pollutants also absorb some uv radiation, leading to warming. Water-soluble chemicals are less likely to deplete ozone. Water-insoluble cfcs and halons are not rained out of the atmosphere. The stratosphere: is a layer of the earth"s atmosphere above the troposphere. The stratosphere contains about 10% of the atmosphere"s air molecules but has 90% of its ozone. Stratospheric ozone absorbs more than 95% of the sun"s uv radiation, which would otherwise reach and damage human, animal, plant, and microbial life. Ozone"s natural cycle: the energy of the sun"s ultraviolet (uv) radiation breaks diatomic oxygen (o2) into atomic oxygen atoms (o). O2 + uv radiation = o + o: a radical oxygen atom reacts with o2 to form an ozone molecule (o3).